Frequency synthesized multichannel radio apparatus

Abstract

A frequency synthesized multichannel radio apparatus comprising a synthesized tranceiver and a remotely mountable control unit. All the possible channel frequencies available to users in a large geographical area are stored in a PROM mounted in the transceiver said PROM serving as a look-up table. The addresses of those channel frequencies in the PROM which are available to a particular user are stored in an electrically alterable storage means, such as an EAROM or a E 2 PROM, contained in the control unit. In normal operation a channel selector in the control unit selects a particular channel in the electrically alterable storage means which in turn reads-out addresses of predetermined locations in the PROM which supplies data for example synthesizer divide numbers to the frequency synthesizer. If the channel frequencies available to a user have to be changed then with the apparatus remaining in situ a data transfer unit which has been preprogrammed with the addresses of the new channel frequencies is connected to the electrically alterable storage means and the new sequence of channel frequency addresses is stored therein.

We claim: 
     
       1. A multichannel radio apparatus comprising in combination: a transceiver including a frequency synthesiser and programmable storage means for storing predetermined channel frequency information; a remotely mountable control unit coupled to said transceiver, said control unit including means for selecting any one of a plurality of channels and an electrically alterable storage means, said electrically alterable storage means storing preselected addresses of locations in the programmable storage means which relate to said predetermined plurality of channels, said control unit further including an externally accessible interface adapted to operatively couple said electrically alterable storage means to a data transfer unit for programming or reprogramming the preselected addresses stored in such electrically alterable storage means to thereby change the channel frequency information for said plurality of channels. 
     
     
       2. An apparatus as claimed in claim 1, wherein said progammable storage means comprises a PROM which stores data to be supplied to said frequency synthesiser. 
     
     
       3. An apparatus as claimed in claim 1, wherein said electrically alterable storage means comprises an EAROM. 
     
     
       4. An apparatus as claimed in claim 1, wherein said electrically alterable storage means comprises an E 2  PROM. 
     
     
       5. An apparatus as claimed in claim 1, wherein said data transfer unit comprises a non-volatile memory for storing data to be used for programming or reprogramming said electrically alterable storage means. 
     
     
       6. An apparatus as claimed in claim 1, wherein said control unit further includes means for inhibiting the power supply to the transceiver when said electrically alterable storage means is being programmed or reprogrammed by said data transfer unit. 
     
     
       7. An apparatus as claimed in claim 6, wherein said control unit further comprises a power supply and said interface includes a connection to said power supply whereby said data transfer unit derives its power from said power supply when programming or reprogramming the electrically alterable storage means. 
     
     
       8. An apparatus as claimed in claim 1, wherein said externally accessible interface comprises a first part of a two-part connector coupled to said control unit by a flexible lead, a second, complementary part of said two-part connector being coupled to said data transfer unit; and wherein said control unit further comprises means to prevent spurious signals from being produced when the data transfer unit is disconnected from the connector and/or allowing extraneous signals from affecting the normal operation of the control unit.